Vehicle passenger restraint systems utilize an airbag which must be inflated quickly in the event of a vehicle crash to provide restraint and cushioning for the occupant. A hybrid inflator can be provided to fill the airbag, the hybrid inflator utilizing a combination of compressed inert gas and the products of combustion of a pyrotechnic heat source. Hybrid inflators are desirable because they generally do not require the use of azides and are hence environmentally-friendly, and the inflation gasses delivered to the airbags are cooler than those from pyrotechnic gas generators, therefore permitting more latitude in the design of associated structures.
However, the use of any pyrotechnic material in the production of inflation gasses creates the possibility of introducing hot products of combustion and associated hot debris from the inflator into the airbag. Although filters may be used to reduce this possibility, the filters add cost, weight, and bulk to the structure and can restrict gas delivery.